Landing gear with threadless cardan joint

Patent metadata

Field	Value
Publication number	US-10414510-B2
Application number	US-201615396195-A
Country	US
Kind code	B2
Filing date	Dec 30, 2016
Priority date	Dec 30, 2016
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

A retractable landing gear includes a main strut having an upper end that is configured to connect to aircraft primary structure and a lower end configured to connect to an axle or bogie truck. An articulated stay has a distal end configured to connect to the aircraft structure and a proximal end pivotally connected to a cardan pin member. The cardan pin member has a cylindrical portion with a first recessed annular channel. The cardan pin member is retained in the socket by a ring assembly formed by two semi-annular ring members that slidably engages the first recessed channel. The ring assembly defines a second recessed annular channel. A collar is configured to be positioned over the second recessed channel, and to contract upon a change in temperature to lockingly engage the second recessed channel, to secure the split ring assembly in the first recessed channel.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A landing gear for an aircraft, the landing gear comprising:
a main strut having a socket;
an articulated stay having a first end;
a cardan pin member pivotably attached to the first end of the articulated stay and further comprising a cylindrical post portion pivotably disposed in the main strut socket, the cylindrical post portion defining a first annular recess disposed below the socket, such that the cardan pin member pivotably attaches the stay to the main strut in a cardan pin joint;
a ring-shaped retainer comprising a first semi-annular ring member and a second semi-annular ring member such that the first and second semi-annular ring members slidably engage the first annular recess cooperatively defining a radially outer surface, the ring-shaped retainer having a maximum transverse dimension, wherein the ring-shaped retainer defines an outwardly-open second annular recess; and
an annular locking collar having a first inner diameter that is greater than the maximum transverse dimension of the ring-shaped retainer during installation such that the annular locking collar can be positioned over the second annular recess, and wherein the annular locking collar is configured to contract to a second inner diameter that is less than the maximum transverse dimension of the ring-shaped retainer by a change in temperature of the locking collar, such that the annular locking collar lockingly engages the second annular recess.

2. The landing gear of claim 1 , wherein the locking collar is configured to be thermally heated to a temperature sufficient to produce the first inner diameter, wherein the locking collar contracts to the second inner diameter to lockingly engage the second annular recess upon cooling to ambient temperature.

3. The landing gear of claim 1 , wherein the locking collar comprises a nitinol alloy and is configured to contract from the first inner diameter to the second inner diameter upon heating the locking collar to a temperature sufficient to induce a martensitic transformation.

4. The landing gear of claim 1 , wherein the annular locking collar is configured to apply a compressive force on the first and second semi-annular ring members during use.

5. The landing gear of claim 1 , wherein the cardan pin member is threadless.

6. The landing gear of claim 5 , wherein the cardan pin member does not have a spline.

7. The landing gear of claim 1 , wherein the main strut is a shock-absorbing strut.

8. The landing gear of claim 1 , wherein the main strut comprises an outer cylinder configured to attach to an aircraft primary structure, and an inner cylinder that slidably engages the outer cylinder, wherein the inner cylinder is configured to attach to a bogie truck, and wherein the inner and outer cylinders define a volume containing a gas and an oil.

9. The landing gear of claim 8 , wherein the gas is nitrogen and the oil is a hydraulic fluid.

10. A method for assembling a landing gear for an aircraft, the landing gear comprising:
a main strut having a socket, and an articulated stay having a first end;
pivotally attaching a cardan pin to the first end of the articulated stay, wherein the cardan pin member comprises a cylindrical post portion;
inserting the cylindrical post portion into in the main strut socket such that the cardan pin member pivotably attaches the stay to the main strut in a cardan pin joint, wherein the cylindrical post portion defines a first annular recess disposed below the socket;
slidably inserting a ring-shaped retainer comprising a first semi-annular ring member and a second semi-annular ring member into the first annular recess such that the first and second semi-annular ring members slidably engage the first annular recess and cooperatively define a radially outer surface, the ring-shaped retainer having a maximum transverse dimension,
locking the ring-shaped retainer in the first annular recess with an annular locking collar having a first inner diameter that is greater than the maximum transverse dimension of the ring-shaped retainer during installation such that the annular locking collar can be positioned over the second annular recess, and wherein the annular locking collar is configured to contract to a second inner diameter that is less than the maximum transverse dimension of the ring-shaped retainer by a change in temperature of the locking collar, such that the annular locking collar lockingly engages the second annular recess.

11. The method of claim 10 , wherein the locking collar is configured to be thermally heated to a temperature sufficient to produce the first inner diameter, wherein the locking collar contracts to the second inner diameter to lockingly engage the second annular recess upon cooling to ambient temperature.

12. The method of claim 10 , wherein the locking collar comprises a nitinol alloy and is configured to contract from the first inner diameter to the second inner diameter upon heating the locking collar to a temperature sufficient to induce a martensitic transformation.

Assignees

• Safran Landing Systems Canada Inc

Inventors

• Schmidt Robert Kyle

Classifications

• F05D2240/14

  Casings or housings protecting or supporting assemblies within · CPC title

• B64C2025/125

  into the fuselage, e.g. main landing gear pivotally retracting into or extending out of the fuselage · CPC title

• B64D29/08 Primary

  Inspection panels for power plants · CPC title

• B64D29/06

  Attaching of nacelles, fairings or cowlings · CPC title

• B64C2001/0072

  from composite materials · CPC title